United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "June 1981," Business Conditions Digest (June 1981) : 66-66. https://fraser.stlouisfed.org/title/43/item/7418/toc/412365 , accessed on May 12, 2024.
United States. Bureau of the Census. "Composite Indexes," in United States. Bureau of the Census. "June 1981," Business Conditions Digest (June 1981) : 66-66. https://fraser.stlouisfed.org/title/43/item/7418/toc/412365 , accessed on May 12, 2024.